Exam 3 (Oral Digestion, Deglutition, Gastric Motility) Flashcards
1
Q
Term for “precipitate of food & saliva”
A
plaque
2
Q
Tooth decay causes formation of _____.
A
plaque
3
Q
_____ and ____ are produced by bacteria which demineralize enamel and attack protein matrix (tooth decay).
A
lactate
protease
4
Q
What is the term for “demineralized enamel and attack of protein matrix”
A
cavities aka caries
5
Q
What substance is in toothpaste that replaces OH groups on hydroxyapatite and kills bacteria?
A
fluoride
6
Q
Lactic acid demineralizes enamel by dissolving _____ in tissue (teeth + bones).
A
CaPO4
7
Q
What is known as the conditioned or learned reflex involved in oral digestion?
A
chew reflex
8
Q
(T/F) Mastication is entirely voluntary.
A
False - mainly voluntary but has involuntary component
9
Q
Stimulus of Chew Reflex
A
presence of food in mouth
10
Q
Chew reflex (stimulates/inhibits) motor neurons of the jaw musculature.
A
inhibits
11
Q
Chew reflex causes reflex (relaxation/contraction) of the jaw.
A
contraction
12
Q
Clinical relevance to chew reflex
A
chewing/stretching jaw while intubating animal
13
Q
Term for “combined secretions of paired salivary glands (parotid, sublingual, submandibular)”
A
saliva
14
Q
2 secretory cell types of salivary glands
A
- parotid (serous - watery saliva)
- sublingual/submandibular (mucoserous - thicker)
15
Q
(T/F) There is small tonic activity of saliva flow in most species between meals but the ruminant has high flow to buffer the rumen.
A
True
16
Q
With meal intake, there is a large (increase/decrease) in salivation.
A
increase
17
Q
Source of saliva
A
extracellular fluid volume
18
Q
(Carnivores/herbivores/omnivores) has much greater saliva production/output due to their dietary niche.
A
herbivores
19
Q
Match amount of saliva production to species:
Horse
Cattle
Dog
Man
A
10 gal/day
40 gal/day
0.5 qt/day
1.5 qt/day
20
Q
Match osmolarity of ECF:
(300 mOsm/L | <300 | > 300)
isotonic
hypotonic
hypertonic
A
300
<300
>300
21
Q
Saliva is used in clinical pathology testing to measure _____ in cattle.
A
heavy metals / chronic lead poisoning
22
Q
What clinical signs are seen with lead poisoning in cattle? Why?
A
neurological signs, blue line near gums
drinks lead water –> lead combines with teeth plaque
23
Q
In non-ruminants, saliva is (hypotonic/hypertonic/isotonic) at low salivary flow rates.
A
hypotonic
24
Q
What are the main ions in saliva of non-ruminants? (4)
A
Na+
Cl-
HCO3-
K+
25
Saliva in non-ruminants (basic/acidic) at low flow rates.
acidic
26
The primary secretion of saliva is in the _____ of the salivary gland while the secretion is modified in the _____.
acini
duct
27
What transporters are used to modify saliva secretions in the salivary duct?
Na/H, Na/K, Na/Cl exchangers
K+ secretion
28
Saliva secretions are modified in the salivary duct only at (low/high) saliva rates.
low
29
If saliva is high flow rate and bypasses modifying transporters, the saliva at the end will be similar to __________ concentration.
extracellular fluid volume
30
What 3 ions are part of the primary salivary secretion at the acinus?
Na, Cl, HCO3
31
In ruminants, salivary flow is (hypotonic/hypertonic/isotonic) at all flow rates.
isotonic
32
In ruminants, salivary flow rate is (high/low) at resting flow rate and (higher/lower) when eating/ruminanting.
high
high
33
In ruminants, ____ is an important buffer in saliva at low flow rates and reciprocates with ____ at higher flow rates.
PO4-
HCO3-
34
Ruminant saliva gets closer to plasma concentration at (low/high) flow rates.
high
35
Ruminant saliva is (acidic/alkaline) with a pH of ____. For what purpose?
alkaline
8
buffers rumen pH (VFA)
36
Ruminants are constantly swallowing to neutralize _____.
VFA
37
pH of healthy rumen
6.5
38
What are the 4 organic components of saliva?
mucin
ptyalin
urea
bacteriocidal compounds
39
Ptyalin is a salivary ______ and only present in (carnivores/herbivores/omnivores).
amylase
omnivores
40
Ptyalin hydrolyzes ____ to _____ which is why bread gets sweeter as you chew.
starches
maltose
41
_____ is important in recycling of the ruminant and passively moves blood into the salivary duct.
urea
42
Urea is lipid (soluble/insoluble) and from ____ of the liver.
soluble
ammonia
43
What are 2 bacteriocidal compounds of saliva?
lysozymes (kill bacteria)
secretory antibody (IgA)
44
Why can licking wounds be beneficial?
secretory antibody (IgA) in saliva can kill some bacteria
45
What is an important source of nitrogen for bacteria of the microbiota needed for growth?
urea
46
Control of salivation is mainly ____.
neural (ANS - PSNS + SNS)
47
What kind of reflexes are in association with preparation for eating?
conditioned reflexes
48
Example of conditioned reflex
pavlov effect
49
What 3 types of input are a part of conditioned reflexes for control of salivation?
visual
auditory
olfactory
50
Unconditioned reflexes for salivation have a(n) _____ and _____ portion.
oral
abdominal
51
Stimulus for unconditioned reflexes (oral portion)
chemical + mechanical presence of food in mouth
52
What 2 receptors sense presence of food in mouth for unconditioned oral reflex for salivation?
tactile receptors
taste receptors
53
Unconditioned reflexes (abdominal portion) for salivation in most animals is associated with _____ stimuli.
noxious
(salivate when nauseous)
54
Why do you salivate when nauseous?
salivary center closely linked with vomiting center
55
3 receptor types in the unconditioned reflexes of salivation (abdominal portion)
esophageal
gastric
intestestinal
56
In the ruminants, ______ in the ____ (part of stomach) stimulates salivation - abdominal portion of unconditioned reflex.
fibrous material
cardia
57
(T/F) All glands receive PSNS & SNS nerves from the CNS.
True
58
What are the PSNS + SNS nerves for salivation from the CNS called?
salivary nuclei
59
Daily efferent output is a mixture of PSNS + SNS control but (PSNS/SNS) dominates fluid content while (PSNS/SNS) dominates releasing salivary enzymes/mucus.
PSNS
SNS
60
PSNS controls _____ of salivation.
SNS controls ___ and ___ of salivation.
fluidity
mucous + enzymes
61
Isolated effect of PSNS on saliva (2)
1. copious watery saliva
2. indirect vasodilation
62
Example of overdosing and having isolated effect of PSNS on saliva
overdose organophosphate insecticide
= down cholinesterase, up Ach = hypersalivation
63
In isolated effect of PSNS on salivation, indirect vasodilation occurs via _____ which leads to increased secretion and saliva flow.
bradykinin
64
Isolated effect of SNS on salivation (2)
1. thick, mucus saliva (direct)
2. vasoconstriction
65
Example cause of isolated SNS effect on salivation
aggressive/excitable dog --> thick mucousy saliva
66
In isolated effect of SNS on salivation, vasoconstriction occurs due to a _____ effect which decreases primary secretion.
alpha adrenergic
67
What hormone has a systemic influence on salivation?
aldosterone
68
Aldosterone increases is there is an increase in what 3 things?
1. dehydration
2. hemorrhage
3. salt-deprivation
69
Four outcomes of aldosterone on distal salivary duct
1. up Na+ reabsorption
2. up K+ secretion
3. down bloodflow to salivary gland
4. down saliva output
70
Which species does aldosterone especially have an effect on in terms of salivation?
ruminants
71
What things increase to increase Na+ reabsorption via aldosterone?
Na+ & K+ channels
Na+ pumps
72
4 functions of saliva in all species
1. soften/lubricates food
2. oral hygiene
3. dissolve chemicals (for taste)
4. thirst sensation
73
In pigs + humans, _____ in saliva allows for starch digestion.
ptyalin
74
What special function does saliva offer to dog/cat that is not in other domestic mammals?
evaporate cooling (10x salivation rate)
75
What 2 special functions does saliva have for ruminants?
1. buffers VFA (in rumen)
2. recycles urea (nitrogen source)
76
Taste buds are ____ bodies composed of what?
ovoid
hair cells + unmyelinated sensory nerve endings
77
What 4 structures are taste buds distributed on?
epiglottis
palate
pharynx
tongue
78
5 tastes of humans
1. salty
2. sour
3. sweet
4. bitter
5. umami (savory)
79
What tastes do we have high threshold for? Which is lowest?
salty/sweet
bitter
80
Why do we have a low threshold for bitter taste?
sense possible plant alkaloids (toxin)
81
Salt taste modality
Na+ (via Na+ channel + ENAC)
82
Sour taste modality
protons (organic acids)
83
Sweet taste modality
hexose
via Tas1r2/3 GPCRs
release ATP to afferent N
84
Which species have a loss of function mutation to sweet tastes?
carnivores (big cats, dolphins)
85
Example of sour organic acid
acetic acid
86
Bitter taste modality
organic cations
--> release ATP to afferent N
87
Example of organic cation for bitter taste
quinine
88
Savory/umami taste modality
glutamate receptor
--> release ATP to afferent N
89
What 3 tastes release ATP to afferent nerves?
sweet
bitter
savory/umami
90
Term for "ability to distinguish tastes/flavors"
taste acuity
91
(T/F) Taste acuity correlates with the number of taste receptors (taste buds).
False - does not correlate
92
3 influences on taste acuity
1. stim. of taste receptors
2. smell
3. food temperature
93
Term for "drive to eat or drink"
nutritional widsom
94
4 drives for nutritional wisdom
1. regulate energy intake
2. water taste
3. salt appetite
4. other nutrients
95
What is the #1 drive to eat or drink?
regulation of energy intake
96
Term for abnormal appetite
pica
97
Term for swallowing
deglutition
98
Term for "common opening to trachea + esophagus"
oropharynx
99
Considering the oropharynx, you must be able to swallow without _____.
aspiration
100
Deglutition is a highly complex reflex requiring _____.
6 cranial nerves
101
3 main phases of swallowing (which are voluntary/involuntary?)
1. oral phase (voluntary)
2. pharyngeal phase (involuntary)
3. esophageal phase (involuntary)
102
Steps of oral phase of deglutition
1. food bolus forms
2. positioned on back of tongue
3. rostral tongue pressed to hard palate, jaw closes --> forces bolus into oropharynx
103
Steps of oral phase of deglutition
1. food bolus forms
2. positioned on back of tongue
3. rostral tongue pressed to hard palate, jaw closes --> forces bolus into oropharynx
104
Function of pharyngeal phase of deglutition
move bolus from oropharynx --> esophagus
105
Stimulus of pharyngeal phase of deglutition
bolus pushed by tongue --> oropharynx
106
Afferent impulses from pressure receptors in oropharynx go to ______ in the medulla/pons that coordinates response (pharyngeal phase of deglutition).
swallowing center
107
Efferent action of pharyngeal phase of deglutition
soft palate- constrictor Mm close off nasopharynx
108
During deglutition, airway opening is (open/closed) and ____ is inhibited for a second to prevent entry of food bolus.
closed
respiration
109
During deglutition, there is contraction of _____ and ____ Mm.
pharyngeal
laryngeal
110
3 actions that occur from contraction of pharyngeal + laryngeal Mm during deglutition
1. larynx raises
2. glottis closes
3. epiglottis covers glottis
111
Contraction of _____ muscles propels bolus through ______ as it relaxes briefly.
pharyngeal Mm
upper esophageal sphincter (UES)
112
After bolus moves through UES, breathing resumes and the bolus entry into upper esophagus initiates ________.
involuntary esophageal phase
113
What 3 steps occur within the esophageal phase of deglutition?
1. primary esophageal peristalsis
2. secondary esophageal peristalsis
3. tertiary esophageal peristalsis
114
During primary esophageal peristalsis, there is (relaxation/contraction) behind the bolus and (relaxation/contraction) in front of the bolus.
contraction
relaxation
115
Relaxation of _____ occurs after the bolus enters the body of the esophagus and remains open until _______ passes.
lower esophageal sphincter (LES)
ring of contraction
116
LES closes completely to prevent ____.
gastric reflux
117
(T/F) Secondary esophageal peristalsis always occurs after primary.
False - only if needed to clear bolus
118
What 2 things induce secondary esophageal peristalsis?
1. uncleared bolus
2. gastric content / reflux
119
In secondary esophageal peristalsis, afferent impulse originates from ______.
esophageal body at bolus (NOT UES!)
120
_____ esophageal peristalsis is in the _____ muscle portion of esophagus and acts (systemically/locally) via _____ nervous system.
tertiary
smooth
locally
esophageal enteric
121
Where should an orogastric feeding tube be placed? Why?
proximal to LES
so LES can open/close normally
122
Esophageal muscle in birds
all smooth muscle (gravity helps)
123
Esophageal muscle in humans/horses
2/3 skeletal, lower 1/3 smooth
124
Esophageal muscle in dog/cat
mostly skeletal (some smooth near LES)
125
Esophageal muscle in ruminants
short segments of smooth M (esophagus groove)
126
Esophageal muscle in rodents
all striated (highly controlled)
127
Peristaltic movement is highly coordinated in the esophagus due to central control from swallowing center which acts through ____.
vagi
128
(Extrinsic/Enteric) innervation dominates control of esophageal peristalsis.
extrinsic
129
Skeletal muscle esophagus neural control in order
swallow center --> GVE nerve (vagal motor N) --> skeletal M
130
Skeletal muscle neural control is by (SNS/PSNS) and at the ____ neuromuscular junction.
PSNS
nicotinic
131
For skeletal muscle esophagus, there is __ motor nerve fiber per __ skeletal M fiber which means (little/lots of) control.
1
1
lots of
132
Name for striated muscle disease and disease example
Vagotomy
myasthenia gravis (autoimmune attach motor endplates for NMJs = difficulty swallowing)
133
Disorder for esophageal amotility if vagus N is cut which causes "food packing"
megaesophagus
134
Smooth muscle esophagus/LES neural control order
swallow center --> vagal PS N --> intrinsic plexi --> effector neurons --> smooth muscle
135
Which type of muscle in the esophagus has serial contractions by coordination of the ENS?
smooth muscle / LES
136
Neural control of the smooth muscle esophagus coordinate with _____ ______ which affects (circular/longitudinal) M while inhibitory nerves relax (circular/longitudinal) M.
muscarinic cholerinergic
longitudinal
circular
137
If you cut both vagi, you will only have ____ esophageal waves.
tertiary
138
What is the main function of the lower esophageal sphincter (LES)?
prevent gastric reflux
relax during swallowing reflex
139
Lower esophageal sphincter is (relaxed/contracted) at rest and (relaxed/contracted) during swallow.
contracted
relaxed
140
During sustained contraction of LES at rest, (circular/longitudinal) smooth muscle via inhibitory nerves is (on/off). On the other hand, (circular/longitudinal) smooth muscle via cholinergic nerves is (on/off).
circular
off
longitudinal
on
141
When LES relaxes during swallow, inhibitory effectors are (on/off) while cholinergic effectors are (on/off).
on
off
142
In the LES, circular smooth muscle is known as ____ fibers while longitudinal is known as ____ fibers.
clasp
sling
143
After a meal, _______ is increased to help enhance contraction of LES to prevent reflux.
plasma gastrin
144
During interdigestive period, ____ are present at LES.
MMCs (migrating motor complexes)
145
What 4 anatomical components are present to help LES to reduce reflux?
1. flutter valve (intraabd esophagus)
2. diaphragm pinching
3. esophagus enters stomach at angle
4. excessive gastric mucosa (horse)
146
Why can't horses vomit?
1. more acute esophageal angle
2. excessive cardia mucosa
3. high LES tone (more smooth M)
147
Term for "failure of LES to open"
achalasia
148
2 motor functions of the simple stomach (oral/proximal part)
1. receive ingested food
2. accommodation (storage)
149
2 motor functions of simple stomach (distal part)
1. mix/grind contents
2. control propulsion
150
Gastric digestion involves the formation of ______ (liquid of dissolved food + HCL + pepsin).
acid chyme
151
During digestion, ingesta is formed into _______.
concentric spheres
152
The (first/last) eaten food is up against gastric mucosa while the (first/last) eaten is in the middle.
first
last
153
(T/F) In the proximal stomach, basic motility pattern is phasic, not tonic.
FALSE - tonic not phasic
154
What does it mean that the proximal stomach is tonic not phasic?
no peristalsis
tonic contractions as stomach empties
155
_______ smooth muscle layer dominates in tonic contractions of the proximal stomach and is (contracted/relaxed) during a meal.
circular
relaxed (for storage)
156
As the stomach empties, there is a(n) (increase/decrease) in circular smooth muscle tone in the proximal stomach.
increase (pushes content --> distal part)
157
What 2 processes allows the proximal stomach to receive and store food?
1. receptive relaxation
2. accommodation
158
Receptive relaxation of proximal stomach order of events
swallowing center --> vagus --> activated inhibitory effector neurons = relaxation of circular smooth muscle
159
During accommodation, tension in the stomach wall can increase significantly without an increase in ______.
intragastric pressure
160
Accommodation in proximal stomach order of events
gastric tension receptor --> CNS --> vagus --> activated inhibitory effector neurons = increase radius + tension
161
During accommodation in the proximal stomach, there is the same increase in ___ and ___, so there is the same _____ at the esophageal sphincter.
radius
tension
pressure
162
As the proximal stomach empties, accommodation (increases/decreases), inhibitory nerve action (increases/decreases), and circular smooth muscle contraction (increases/decreases). Why?
decreases
decreases
increases
forces residual content --> distal part
163
In the distal stomach, basic motility pattern is peristalsis driven by ______.
pacemaker
164
3 main functions of the distal stomach
1. propulsion
2. emptying
3. retropulsion
165
What occurs during propulsion (of distal stomach)?
pylorus opens so content can go in
166
What occurs during emptying (of distal stomach)
pylorus is open
chyme exits
mixing + grinding
167
What occurs during retropulsion (of distal stomach)?
pylorus narrows
moves solid matter
168
Pigs are fed "fines" for fattening but decrease diet bulk which (increases/decreases) acid chyme and causes _____.
increases
proximal stomach ulcers
169
What is the "fed pattern" in distal stomach?
volume/presence of food --> stomach empties faster
170
What two things sense contents of food in the stomach?
mechanoreceptors
chemoreceptors
171
What 2 things mediate gastric motility/emptying in distal stomach?
1. neural activity
2. hormones (gastrin)
172
When mechanoreceptors + chemoreceptors sense food in stomach, they respond by (increase/decrease) motility in what 2 areas?
increase
stomach + colon
173
What 2 neural stimuli lead to release of gastrin?
cholinergic neurons
GRP (gastrin releasing peptide)
174
What 2 luminal stimuli lead to release of gastrin?
amino acids
increased pH (pH > 4)
175
Response to gastrin
increased gastric motility + emptying
176
What 2 things mediate feedback (inhibitory) control of gastric motility/emptying in distal stomach?
1. enterogastric long reflex (neural)
2. CCK + incretins (hormonal)
177
What 3 receptor types stimulate afferent pathway for feedback/inhibitory control of distal stomach motility?
1. duodenal osmoreceptors
2. duodenal pH receptors
3. stretch receptors
178
Duodenal hypertonicity leads to (more/less) gastric emptying in distal stomach while hypotonicity leads to (more/less).
less
more
179
Why does duodenal hypertonicity cause less gastric emptying?
allow more time to dilute content in the duodenum
180
When duodenal pH is >3.5-4 there is (more/less) gastric emptying in the distal stomach. When pH is <3.5-4 there is (more/less) emptying.
more
less
181
Why is there less gastric emptying of the distal stomach when the duodenal pH is <3.5-4?
time to neutralize acid w/ bicarb secretion + pancreatic juice
182
When duodenum is full, there is (more/less) gastric emptying. When empty, there is (more/less) gastric emptying.
less
more
183
Why is there less gastric emptying when duodenum is full?
time for passage of content in duodenum
184
Reduced gastric motility/emptying is mediated by what 2 things?
1. activation of SNS efferents
2. deactivation of PSNS efferents
185
CCK released by what 2 stimuli?
lipids of 12-18 C atoms
amino acids
186
CCK is a _____ at the gastrin receptor.
partial agonist
187
If high gastrin concentration in blood, (increase/decrease) gastric motility by CCK. If low gastrin, (increase/decrease motility.
decrease
increase
188
GLP 1&2 release is stimulated by ____ in intestinal lumen.
CHO
189
GLP 1&2 lead to (increase/decreased) gastric motility mainly by GLP (1/2).
decreased
1
190
Order the following with how quickly of gastric emptying: (fastest to slowest)
low fat diets
high fat diets
liquid
liquid
low fat
high fat
191
Between meals (interdigestive period) _____ clears bulk from stomach to large intestine.
MMCs (migrating motor complexes)
192
Phase I MMCs
slow waves | no contraction
193
Phase II MMCs
intermittent spiking of slow waves (spike potentials)
194
Phase III MMCs
spikes at each crest of slow waves = train of peristaltic contractions
195
Which hormones provides neurocrine cholinergic action in Phase III of MMCs?
motilin
196
______ remains open to clear stomach during interdigestive period w/ MMCs.
pylorus
197
Phases of MMCs repeat every _____ and are immediately stopped by what?
2 hours
eating
198
Tetanic contractions after 24 - 72 hours after stomach empties are known as:
hunger pangs
199
Hunger contractions occur ______ hours after stomach empties by increasing phase ____ of MMCs.
12 -24
3
200
After 24 - 72 hours, intense rhythm of peristaltic contractions fuse into _____ contractions.
tetanic contractions
